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<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
<script>
var obj = new Object(); //{}
obj.species = '动物';
function Animal() {
}
Animal.prototype = obj;
function Person() {

}
Person.prototype = new Animal();

var su = new Person();
console.log(su.species,su.__proto__,su.toString());

</script>
</body>
</html>